2 years ago

How can you use Hess’s law to determine a reaction’s enthalpy?

1 answer:

3 0

Hess law is due to enthalpy being a state function, which allows us to calculate the overall change in enthalpy by simply summing up changes for each step of the way, until product is formed. All steps have to proceed at the same temperature and the equations for the individual steps must balance out.

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_____ energy is energy available to do work.

Arisa [49]

The answer is C. Free Energy.

Activation energy is the energy that must be exceeded before a chemical reaction can occur. Free energy best describes as energy available to do work.

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2 years ago

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In a lab, the mass of object A is 2.5 kg. Object A weighs:

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24.5 N hope it helps

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3 years ago

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How many molecules are in 23 Moles of oxygen o2

loris [4]

Answer:

1.38×10^25 molecules

Explanation:

Applying n= (no. of molcules)/NA

23 = N/6.02×10^23

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Why does a solution of acid and sodium thiosulfate go cloudy

klemol [59]

The soulustion. turn cloudy due to the precipitation of Sulphur.

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600 s after initiation of a first order reaction 48.5% of the initial reactant concentration remains present. What is the rate c

Ludmilka [50]

Answer:

$k=1.20x10^{-3} s^{-1}$

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For a first order reaction the rate law is:

$v=\frac{-d[A]}{[A]}=k[A]$

Integranting both sides of the equation we get:

$\int\limits^a_b {\frac{d[A]}{[A]}} \, dx =-k\int\limits^t_0 {} \, dt$

where "a" stands for [A] (molar concentration of a given reagent) and "b" is {A]0 (initial molar concentration of a given reagent), "t" is the time in seconds.

From that integral we get the integrated rate law:

$ln\frac{[A]}{[A]_{0} } =-kt$

$[A]=[A]_{0}e^{-kt}$

$ln[A]=ln[A]_{0} -kt$

$k=\frac{ln[A]_{0}-ln[A]}{t}$

therefore k is

$k=\frac{ln1-ln0,485}{600}=1,20x10^{-3}$

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3 years ago